Treatment decisions traced back to diagnosing urologists

New research from MD Anderson Cancer Center is shedding light on the important role a diagnosing urologist plays in determining whether older men with low-risk prostate cancer receive treatment for their disease, and if so, what type of treatment they receive.

The study, published in JAMA Internal Medicine, examined why active surveillance, which involves monitoring the cancer closely with prostate-specific antigen (PSA) blood tests, digital rectal exams, and ultrasounds and biopsies at regular intervals to see if the cancer is growing, is underused in this patient population.

According to the American Cancer Society, 233,000 new cases of prostate cancer will be diagnosed this year, making it the most common non-skin cancer in men. Because prostate cancer often grows very slowly, some men — especially those who are older or have serious health problems — may never need treatment for their prostate cancer. Previous studies have shown mortality rates in this older population are similar for those who opt for surveillance versus treatment. Yet many men continue to incur unnecessary treatment harms, such as incontinence and erectile dysfunction.

“What’s striking is just how much variation exists in managing prostate cancer, with the diagnosing physician playing as much a role, if not more of a role, than accepted patient factors that impact surveillance use,” said Karen Hoffman, M.D., assistant professor in Radiation Oncology and lead author.

Using the National Cancer Institute’s Surveillance, Epidemiology and End Results (SEER) registry, which compiles U.S. cancer statistics, researchers identified 12,068 men ages 66 and older who were diagnosed with low-risk prostate cancer from 2006-2009. Their physicians’ characteristics were obtained from linked Medicare claims to determine variations attributable to medical degree, year of training, training location and board certifications.

Researchers also set out to determine the impact of the diagnosing urologist on treatment decisions, quantify the rate of surveillance versus treatment and identify urologist and patient factors associated with surveillance selection.

Results Indicate Widespread Differences

Of the 12,068 men studied, 80% received treatment and only 20% underwent observation. Observation rates varied significantly across urologists, from 4.5 to 64.2%, and radiation oncologists, from 2 to 47%.

Interestingly, researchers found the diagnosing urologist accounted for more than double the rate of variation seen in treatment-versus-observation decisions, compared to individual patient characteristics such as age, co-morbidities and PSA level.

Patients diagnosed by urologists who treated low-risk prostate cancer were more likely to receive treatment, and when treated, more likely to receive a therapy their diagnosing urologist used. Hoffman said these findings suggest that physicians not only influence decision making, but the type of treatment selected.

For example, the research found that patients diagnosed by urologists who billed for external beam radiation therapy were more likely to receive it, bringing financial considerations into the fold. The study could not determine those physicians with ownership interests in radiation equipment.

The authors note public reporting of physicians’ cancer management prescribing practices would enable primary care providers and patients to make more informed decisions when selecting a physician to diagnose and treat their prostate cancer.

“Primary care physicians play a key role because they refer patients to urologists for elevated PSA levels and prostate biopsies. Increasing transparency could lead to selecting physicians more open to surveillance,” Hoffman said.

The authors note several limitations to the study. Those included shifting practice patterns that may influence treatment decisions and the inability to measure certain factors that may impact treatment choice, such as family history and patient anxiety.

Follow-up work will evaluate whether patient counseling in a multidisciplinary setting and patient decision aids increase active surveillance acceptance.

Disclosures: Hoffman receives research support from the American Society for Radiation Oncology and Benjamin Smith receives funding from Varian Medical Systems.